Measurement instrument having time, frequency and logic domain channels

ABSTRACT

A measurement apparatus is provided for measuring signals from a device under test (DUT). The measurement apparatus includes a time domain receiver configured to receive from the DUT a time domain signal in a time domain; a logic domain receiver configured to receive from the DUT a logical signal comprising logic levels over time; a frequency domain receiver configured to receive from the DUT a frequency domain signal in a frequency domain through frequency downconversion; and a controller coupled to the logic domain receiver, and configured to determine the logic levels over time of the logical signal and to control at least one parameter of the frequency domain signal in response to the determined logic levels.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation under 37 C.F.R. § 1.53(b)(1)of commonly owned U.S. Pat. Application No. 16/552,522 to Ken A.Nishimura, filed on Aug. 27, 2019, which claims priority under 35 U.S.C.§ 119(e) from U.S. Provisional Application 62/753,685 filed on Oct. 31,2018, which names Ken A. Nishimura as the inventor. The presentapplication claims priority under 35 U.S.C. § 120 to U.S. Pat.Application No. 16/552,522, the disclosure of which is specificallyincorporated herein by reference in its entirety.

BACKGROUND

Generally, electromagnetic signals, including radio frequency (RF)signals, may be captured and represented in the time domain and thefrequency domain. Representation in the time domain shows the amplitudeof the signals versus time, and representation in the frequency domainshows the amplitude of the signals versus frequency. Traditionally, anoscilloscope is used to represent signals in the time domain, and aspectrum analyzer is used to represent signals in the frequency domain.However, oscilloscopes can now represent signals in the frequencydomain, as well, by performing a fast Fourier transform (FFT) of a timedomain signal, and displaying the frequency spectrum of a capturedsignal in addition to, or in lieu of a time-domain representation.

These oscilloscopes, referred to as “multi-domain oscilloscopes,”include a separate frequency domain channel, in addition to a timedomain channel. In a multi-domain oscilloscope, the frequency domainchannel includes analog frequency downconversion, with optionalfiltering of incoming signals prior to digitization, in order to improvefidelity of the captured waveform. This is an alternative to performingan FFT on a captured time domain signal in a time domain channel. As analternative to analog frequency downconversion, wideband digitizationcan be performed in the frequency domain channel, commonly referred toas digital down-conversion (DDC), which is typically followed byfiltering and decimation.

However, frequency domain and time domain channels suffer from frequencylimitations. Typically, wideband analog frequency translation stages arelimited in input frequency to a few GHz. Extending the range requirescareful frequency planning, which may result in an implementation beyondthe scope of a time domain instrument. Digital down-conversion requiresthat the digitizer be able to process the full bandwidth of the incomingsignal. The bandwidth may necessarily be greater than the instantaneousbandwidth. For example, a 1 GHz bandwidth signal centered at 10 GHzrequires a digitizer capable of 10.5 GHz signals (21 GSa/s) to DDC, asopposed to a 2 GSa/s digitizer. Neither is amenable to a mmWave systemwhere the input frequencies are typically between 60 and 90 GHz or more.

Wideband oscilloscopes are well suited for analysis of mm Wave RFsignals, since the bandwidths of interest of mmWave RF signals exceedthe bandwidth capabilities of typical frequency domain instruments, suchas conventional spectrum analyzers. For example, the 60 GHz unlicensedband extends from about 57 GHz to about 64 GHz (7 GHz of analysisbandwidth), and automotive RADAR extends from about 76 GHz to about 81GHz (5 GHz of analysis bandwidth). In comparison, most spectrumanalyzers are limited to 2 GHz of analysis bandwidth, and are thereforenot helpful. Accordingly, in order to perform frequency domain analysisof such wideband RF signals, a wideband oscilloscope may be used in FFTmode. Because of the high carrier frequency of mmWave RF signals, directdigitization requires a very high sampling rate in the digitizer tosatisfy the Nyquist criterion, and is not a practical option for mostinexpensive oscilloscopes. Similarly, a general purpose analogdownconverter for performing frequency down conversion on a frequencydomain signal is unlikely to have sufficient performance at thesefrequencies. Rather, because of the banded characteristics of thesesystems, optimized mixers or downconverters are utilized for each bandof interest. Therefore, what is needed is a convenient source of asignal to act as the downconverting LO for the chosen mixer.

BRIEF SUMMARY

According to representative embodiments, a measurement apparatusincludes a time domain receiver configured to receive a time domaininput signal in a time domain; a logic domain receiver configured toreceive a logical signal comprising logic levels over time; and afrequency domain receiver configured to receive a frequency domainsignal in a frequency domain through frequency downconversion. Themeasurement apparatus may further include a controller coupled to thelogic domain input to determine the logic levels over time as determinedlogic levels.

BRIEF DESCRIPTION OF THE DRAWINGS

The example embodiments are best understood from the following detaileddescription when read with the accompanying drawing figures. It isemphasized that the various features are not necessarily drawn to scale.In fact, the dimensions may be arbitrarily increased or decreased forclarity of discussion. Wherever applicable and practical, like referencenumerals refer to like elements.

FIG. 1 illustrates a system that includes a measurement instrumenthaving time, frequency and logic domain channels, in accordance with arepresentative embodiment.

FIG. 2 illustrates another system that includes a measurement instrumenthaving time, frequency and logic domain channels, in accordance with arepresentative embodiment.

FIG. 3 illustrates a measurement instrument having time, frequency andlogic domain channels, in accordance with a representative embodiment.

FIG. 4 illustrates another system that includes a measurement instrumenthaving at least time and frequency domain channels, an internal localoscillator (LO) signal generator and LO port, in accordance with arepresentative embodiment.

FIG. 5 illustrates a controller in a measurement instrument having time,frequency and logic domain channels, in accordance with a representativeembodiment.

FIG. 6 illustrates an operational process for a measurement instrumenthaving time, frequency and logic domain channels, in accordance with arepresentative embodiment.

FIG. 7 illustrates another operational process for a measurementinstrument having at least time and frequency domain channels, aninternal LO signal generator and LO port, in accordance with arepresentative embodiment.

FIG. 8 illustrates another operational process for a measurementinstrument having at least time and frequency domain channels, aninternal LO signal generator and LO port, in accordance with arepresentative embodiment.

DETAILED DESCRIPTION

In the following detailed description, for purposes of explanation andnot limitation, representative embodiments disclosing specific detailsare set forth in order to provide a thorough understanding of anembodiment according to the present teachings. Descriptions of knownsystems, devices, materials, methods of operation and methods ofmanufacture may be omitted so as to avoid obscuring the description ofthe representative embodiments. Nonetheless, systems, devices, materialsand methods that are within the purview of one of ordinary skill in theart are within the scope of the present teachings and may be used inaccordance with the representative embodiments. It is to be understoodthat the terminology used herein is for purposes of describingparticular embodiments only, and is not intended to be limiting. Thedefined terms are in addition to the technical and scientific meaningsof the defined terms as commonly understood and accepted in thetechnical field of the present teachings.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements or components, theseelements or components should not be limited by these terms. These termsare only used to distinguish one element or component from anotherelement or component. Thus, a first element or component discussed belowcould be termed a second element or component without departing from theteachings of the present disclosure.

The terminology used herein is for purposes of describing particularembodiments only, and is not intended to be limiting. As used in thespecification and appended claims, the singular forms of terms “a”, “an”and “the” are intended to include both singular and plural forms, unlessthe context clearly dictates otherwise. Additionally, the terms“comprises”, and/or “comprising,” and/or similar terms when used in thisspecification, specify the presence of stated features, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, elements, components, and/or groups thereof. As usedherein, the term “and/or” includes any and all combinations of one ormore of the associated listed items.

Unless otherwise noted, when an element or component is said to be“connected to”, “coupled to”, or “adjacent to” another element orcomponent, it will be understood that the element or component can bedirectly connected or coupled to the other element or component, orintervening elements or components may be present. That is, these andsimilar terms encompass cases where one or more intermediate elements orcomponents may be employed to connect two elements or components.However, when an element or component is said to be “directly connected”to another element or component, this encompasses only cases where thetwo elements or components are connected to each other without anyintermediate or intervening elements or components.

In view of the foregoing, the present disclosure, through one or more ofits various aspects, embodiments and/or specific features orsub-components, is thus intended to bring out one or more of theadvantages as specifically noted below. For purposes of explanation andnot limitation, example embodiments disclosing specific details are setforth in order to provide a thorough understanding of an embodimentaccording to the present teachings. However, other embodimentsconsistent with the present disclosure that depart from specific detailsdisclosed herein remain within the scope of the appended claims.Moreover, descriptions of well-known apparatuses and methods may beomitted so as to not obscure the description of the example embodiments.Such methods and apparatuses are within the scope of the presentdisclosure.

FIG. 1 illustrates a system that includes a measurement instrumenthaving time, frequency and logic domain channels, in accordance with arepresentative embodiment.

In FIG. 1 , the system 10A includes a measurement instrument, such asoscilloscope 100A having time, frequency and logic domain channels formeasuring signals from a DUT 199 (device under test). The DUT 199 inFIG. 1 is representative of a communications device that emits signalsin any or all of a time domain channel, a frequency domain channel,and/or a logic domain channel. An example of the DUT 199 in FIG. 1 is amobile device such as a cellular telephone. The oscilloscope 100A inFIG. 1 is an oscilloscope system representative of a measurementinstrument (or measurement apparatus) having time, frequency and logicdomain channels. The oscilloscope 100A in FIG. 1 is used to measure thesignals from the DUT 199, including signals in the time domain channel,the frequency domain channel, and/or the logic domain channel. Inalternative embodiments, the measurement instrument may have a timedomain channel and either a frequency domain channel or a logic domainchannel, without departing from the scope of the present teachings. Thefrequency domain channel may be optimized to deal with an analysisbandwidth that may be a small fraction of the actual frequency of thesignal (e.g. the carrier frequency of a mmWave signal).

The oscilloscope 100A includes a time domain input 110 (e.g., timedomain channel, including a receiver), a logic domain input 120 (e.g.,logic domain channel, including a receiver), a frequency domain input130 (e.g., frequency domain channel, including a receiver), a controller140, an acquisition system 150, and an outer enclosure 101. The timedomain input 110 (receiver) receives DUT time domain output signal 111from the DUT 199 and may include a time domain receiver and/or otherelements used to process the DUT time domain output signal 111 in thetime domain channel. The time domain input 110 may include elements suchas analog-to-digital converters, comparators, amplifiers, attenuatorsand digital processing elements such as memories and decimators, asknown in the art, and configured to sample the DUT time domain outputsignal 111 for analysis in the time domain.

The logic domain input 120 (receiver) receives a DUT logic domain outputsignal 121 (logical signals) from the DUT 199 and may include a logicdomain receiver and/or other elements used to process the DUT logicdomain output signal 121 (logical signals) in the logic domain channel.The frequency domain input 130 (receiver) receives the DUT frequencydomain output signal 131 from the DUT 199 and may include a frequencydomain receiver and/or other elements used to process the DUT frequencydomain output signal 131 in the frequency domain channel, as known inthe art.

The time domain input 110 provides a time domain input signal 112 in atime domain as a first input signal. The logic domain input 120 providesa logic level input signal 122 as a second input signal. Generally, thelogic domain input 120 is configured to capture a signal, and ascertaina digital value represented by the signal. In some embodiments, thelogic domain input 120 may be considered a one-bit quantizer, where thesignal is interpreted as a logic zero when the input is below athreshold and as a logic one when the input is above the threshold. Thefrequency domain input 130 provides a frequency domain input signal 132as a third input signal through frequency downconversion. One or more ofthe time domain input 110, the logic domain input 120 and the frequencydomain input 130 may operate under control of the controller 140. Thatis, the controller 140 is effectively a common controller enabling acorrelated relationship (interoperation) among the time domain input110, the logic domain input 120 and the frequency domain input 130, suchthat data from any of the time domain input 110, the logic domain input120 and the frequency domain input 130 may be used to control andcoordinate operations of any others of the time domain input 110, thelogic domain input 120 and the frequency domain input 130. Likewise, thecontroller 140 may control and coordinate operations of the time domaininput 110, the logic domain input 120 and the frequency domain input 130according to common timing.

For example, logic levels of the DUT logic domain output signal 121(logical signals), which may provide voltage levels, for example,corresponding to digital data values over time, may be used by thecontroller 140 to trigger functionality of the time domain input 110and/or the frequency domain input 130. For example, the logic levels mayrepresent one or more parameters of the DUT frequency domain outputsignal 131, and acquisition of the DUT frequency domain output signal131 by the frequency domain input 130 may be triggered based onrespective states of the logic levels from the DUT logic domain outputsignal 121. Likewise, the controller 140 may monitor the time domaininput 110 and, when it determines a particular signal threshold isexceeded, triggers sampling of the signal (e.g., taking 1024 samples) inthe frequency domain input 130. FFT and averaging may then be performedon the samples, as is known in the art. Similarly, a data burst may besent through the time domain input 110, which is detected by thecontroller 140, which flags a corresponding portion of the signal fromthe frequency domain input 130 to be displayed as a frequency spectrum.Also, the frequency domain input 130 may be acquired based onacquisition frequencies, discussed below, set in advance by the logiclevels of the DUT logic domain output signal 121. The logic level inputsignal 122 may, for example, represent a variable center frequency forcommunications from the DUT 199.

The controller 140 may include a memory that stores instructions and aprocessor that executes the instructions. An example of the controller140 is illustrated in and described with respect to FIG. 5 below. Thecontroller 140 is coupled physically and/or logically (e.g., by a dataconnection) to the logic domain input 120 to determine the logic levels123 of the logic level input over time. The frequency domain input 130is controlled by the controller 140 to provide the frequency domaininput signal 132 (third input signal) through frequency downconversion.For example, at least one parameter of the frequency domain input signal132 (third input signal) may be controlled by control signals 141determined by the controller 140 in response to the logic levels 123from the logic domain input 120 such that the at least one parameter maythen be provided to the frequency domain input 130. Although thecontroller 140 is shown internal to the oscilloscope 100A, thecontroller 140 may be implemented by a processor or other control devicethat is outside the oscilloscope 100A, such as a personal computer (PC)or a workstation, for example, without departing from the scope of thepresent teachings.

The acquisition system 150 acquires time domain input signal 112 fromthe time domain input 110, logic level input signal 122 from the logicdomain input 120, and frequency domain input signal 132 from thefrequency domain input 130. The acquisition system 150 producesoscilloscope output(s) 152 based on one or more of the time domain inputsignal 112 (first input signal), the logic level input signal 122(second input signal) and the frequency domain input signal 132 (thirdinput signal) acquired by the acquisition system 150 from the timedomain input 110, the logic domain input 120 and the frequency domaininput 130. The oscilloscope output(s) 152 may be provided to a displayprocessor, which formats the oscilloscope output(s) 152 for display on adisplay device (not shown in FIG. 1 ). For example, each of the timedomain input signal 112 and the logic level input signal 122 may bedisplayed as amplitude (voltage) over time, where the logic level inputsignal 122 in particular is displayed as a stream of high and lowvoltage values corresponding to the logic levels of the logic levelinput signal 122.

The at least one parameter of the frequency domain input signal 132(third input signal) controlled by the controller 140 may be anacquisition frequency, which is the range of frequencies of the signalfrom the DUT to which the oscilloscope 100A (e.g., the acquisitionsystem 150) is responsive after downconversion of the DUT frequencydomain output signal 131 to the frequency domain input signal 132. Thedownconversion is a function of a local oscillator (LO) frequency of theLO signal provided by a LO signal generator, which may be controlled bythe controller 140, as discussed below with reference to FIGS. 2-4 . Inparticular, a mixer mixes an input signal, such as the DUT frequencydomain output signal 131, and the LO signal to provide an intermediatefrequency (IF) signal having a downconverted frequency. The value of thedownconverted frequency is adjustable as a function of the value of theLO frequency, which may be determined by the controller 140. In terms ofthe mixer, acquisition frequencies are those frequencies applied at theradio frequency (RF) input to the mixer, which after frequencydownconversion, appear at the IF output of the mixer within a range offrequencies acceptable by the IF channel (or frequency domain channel).

Another parameter that may be controlled by the controller 140 is theamplitude of the frequency domain input signal 132. To the extent thatthe mixer is linear, the amplitude of the LO signal will change theamplitude of the resultant IF signal. More generally, it is desired tocontrol the amplitude of the LO signal to be in a relationship with RFamplitude, so that the mixer operates as linearly as possible.

The controller 140 may be coupled to the logic domain input 120 todetermine the logic levels of the logic level input signal over time.The controller 140 may then generate control signals 141 in response tothe logic levels 123.

A special case arises when the signal presented at the frequency domaininput 130 incorporates spread spectrum processing. Spread spectrumprocessing is used to distribute the modulated signal across a muchwider bandwidth for purposes of evasion or interference mitigation,e.g., as in Wi-Fi or Bluetooth. A specific subset of spread spectrumprocessing involves frequency hopping, according to which a narrowbandsignal is “hopped” across a much wider bandwidth according to apredetermined sequence. The predetermined sequence enables alignment ofthe transmitter and the receiver. The occupied bandwidth at any instantremains narrow, while the center frequency of the DUT frequency domainoutput signal 131 is updated hundreds or even thousands of times asecond, for example. Thus, knowledge of the center frequency at anyinstant is required in order to analyze the DUT frequency domain outputsignal 131 without capturing the entire wider bandwidth. That is, thefrequency domain channel would not be able to perform anydown-conversion as the desired signal could be anywhere within theentire wider bandwidth of the frequency domain channel. Hence the systemwould not benefit from band-limiting and down-conversion. The frequencyhopping may be controlled digitally, e.g., with a digital algorithmproviding inputs to the frequency hopping system, such as using aFrequency Control Word (FCW), which represents the center frequency of ahopped signal. Analyzing the FCW will indicate the frequency of thedesired signal.

Thus, an example usage of the embodiment of FIG. 1 is when the DUTfrequency domain output signal 131 presented at the frequency domaininput 130 incorporates spread spectrum processing. In FIG. 1 , thecenter frequency of the desired signal may be controlled according to apredetermined sequence using the logic domain input 120. For example, analgorithm processed by a digital signal processor in the logic domaininput 120 or by the controller 140 may provide inputs such as a FCW,representative of the center frequency of a hopped signal. In general,the FCW may be a digital signal on the DUT 199. The controller 140receives the FCW through the logic domain input 120, where the DUT logicdomain output signal 121 may represent the FCW. The digital values ofthe logic level input signal 122 are interpreted by the controller 140as the FCW. Alternatively, the controller 140 may be programmed with thesame algorithm used to generate the FCW in the DUT 199, and the logiclevels of the logic level input signal 122 are used as a time-trigger,or synchronization. The FCW indicates the frequency of the desiredsignal presented, or to be presented, to the frequency domain input 130.The net result may be that frequency translation is incorporated withinthe frequency domain input 130 to track the frequency hopping asdescribed by the FCW applied to the logic domain input 120. That is, thefrequency hopping component may be removed, thereby minimizing thebandwidth required to analyze the DUT frequency domain output signal131. This enables the “de-hopped” signal of interest to occupy theintended bandwidth used by the frequency domain input 130. Of course,the digital data presented to the logic domain input 120 is not limitedto a FCW or to frequency hopping systems generally.

FIG. 2 illustrates another system that includes a measurement instrumenthaving time, frequency and logic domain channels, in accordance with arepresentative embodiment.

In FIG. 2 , a system 10B for analyzing RF signals includes anoscilloscope 100B, an external filter 161 and an external mixer 162. Theoscilloscope 100B is a measurement apparatus, and includes at least thesame elements of the oscilloscope 100A shown in FIG. 1 , although notall of these elements are shown in FIG. 2 for the sake of convenience.The oscilloscope 100B of FIG. 2 additionally details the frequencydomain input 130. It is understood, however, that FIG. 2 includes thetime domain input 110, the logic domain input 120 and the frequencydomain input 130, or any combination of two of the time domain input110, the logic domain input 120 and the frequency domain input 130, andthat the controller 140 may commonly control and coordinate operationsof the same.

Specifically, in the embodiment of FIG. 2 , the frequency domain input130 includes an integrated (internal) LO signal generator 133 and a LOoutput port 134. The external mixer 162 is provided outside the outerenclosure 101 of the oscilloscope 100B. The external mixer 162 receivesthe DUT frequency domain output signal 131 from the device under test(not shown in FIG. 2 ) via an external filter 161 which is optional, forexample. The external mixer 162 also receives an LO signal 135 from theLO output port 134. The LO signal 135 is generated by the LO signalgenerator 133, which is provided inside the outer enclosure 101. In analternative configuration, the LO signal generator 133 may be anexternal LO signal generator that is provided outside the outerenclosure 101, as is the external mixer 162. In this alternativeconfiguration, the controller 140 may control and coordinate operationsin the same manner as with an internal LO signal generator 133, asdiscussed below with reference to FIG. 3 . The LO signal generator 133provides the LO signal 135 to the LO output port 134, and the LO outputport 134 provides the LO signal 135 to the external mixer 162. Theoutput of the external mixer 162 is a frequency downconvertedintermediate frequency (IF) signal 136. The frequency downconverted IFsignal 136 is provided to an IF filter 137, which is optional and whichprovides the (filtered) frequency domain input signal 132 as an output.

Characteristics of the LO signal 135 may be controlled based on LOcontrol signals 147 from the controller 140, and the external mixer 162may generate the frequency downconverted IF signal 136 based on the LOsignal 135, as discussed above. In an illustrative implementation ofFIG. 2 , logic levels (i.e., from the logic domain input 120) may beprovided to the controller 140, and in response, the controller 140 mayoutput the LO control signals 147 to the LO signal generator 133 tocontrol the characteristics of the LO signal 135 generated by the LOsignal generator 133 based on the logic levels.

FIG. 3 illustrates a measurement instrument having time, frequency andlogic domain channels, in accordance with a representative embodiment.

In FIG. 3 , an oscilloscope 100C is a measurement apparatus. Theoscilloscope 100C includes at least the same elements of theoscilloscope 100A shown in FIG. 1 , although not all of these elementsare shown in FIG. 3 for the sake of convenience. The oscilloscope 100Cin FIG. 3 also details the frequency domain input 130. It is understood,however, that FIG. 3 includes the time domain input 110, the logicdomain input 120 and the frequency domain input 130, or any combinationof two of the time domain input 110, the logic domain input 120 and thefrequency domain input 130, and that the controller 140 may commonlycontrol and coordinate operations of the same.

Specifically, in the embodiment of FIG. 3 , the frequency domain input130 includes a filter 138 which is optional, an internal LO signalgenerator 133, an internal mixer 139, and an optional IF filter 137. Theinternal LO signal generator 133 and the internal mixer 139 are providedwithin the outer enclosure 101 of the oscilloscope 100C. The internalmixer 139 receives the DUT frequency domain output signal 131 from thedevice under test (not shown in FIG. 3 ) via the filter 138. Theinternal mixer 139 also receives the LO signal 135 from the LO signalgenerator 133. The LO signal 135 is generated by LO signal generator133, which is an integrated local oscillator signal generator. The LOsignal generator 133 provides the LO signal 135 to the internal mixer139, e.g., under control of the controller 140. The output of theinternal mixer 139 is a frequency downconverted IF signal 136. Thefrequency downconverted IF signal 136 is provided to an IF filter 137,which outputs the frequency domain input signal 132. The controller 140controls interoperation among the internal LO signal generator 133, theinternal mixer 139 and each of the time domain input 110, the logicdomain input 120 and the frequency domain input 130, such thatparameters of the internal LO signal generator 133 and/or the internalmixer 139 may be adjusted in response to data from any of the timedomain input 110, the logic domain input 120 and the frequency domaininput 130, or data from the internal LO signal generator 133 and/or theinternal mixer 139 may be used to control operations of the time domaininput 110, the logic domain input 120 and the frequency domain input130. For example, the controller 140 may use prior knowledge of theinternal mixer 139 and LO characteristics of the LO signal 135 to avoidbad combinations.

As discussed above, characteristics of the LO signal 135 may becontrolled based on control signals 141 from the controller 140, and theinternal mixer 139 may generate the frequency downconverted IF signal136 based on the LO signal 135, as discussed above. In an illustrativeimplementation of FIG. 3 , logic levels (i.e., from the logic domaininput 120) may be provided to the controller 140, and the controller 140may output the control signals 141 in response to the logic levels tothe LO signal generator 133. The LO signal generator 133 generates theLO signal 135 based on the control signals 141 from the controller 140.In the embodiment of FIG. 3 , all of the functionality of the frequencydomain input 130, including the internal mixer 139, is provided withinthe outer enclosure 101 of the oscilloscope 100C.

FIG. 4 illustrates another system that includes a measurement instrumenthaving at least time and frequency domain channels, internal(integrated) LO signal generator and LO port, in accordance with arepresentative embodiment.

In FIG. 4 , system 40 for analyzing signals includes a measurementinstrument, such as oscilloscope 400, having time, frequency and logicdomain channels, and an internal LO signal generator 433, as well as anexternal mixer 462. A DUT 499 (device under test) in FIG. 4 isrepresentative of a communications device that emits signals in any orall of an analog time domain channel, a frequency domain channel, and/ordigital time domain (logic) channels. An example of the DUT 499 in FIG.4 is a mobile device such as a cellular telephone. The oscilloscope 400in FIG. 4 is representative of a measurement apparatus having analogtime domain, radio frequency (RF) domain and digital time domain (logic)channels, although other types of measurement instruments may beincorporated without departing from the scope of the present teachings.The oscilloscope 400 in FIG. 4 is used to measure and/or display thesignals from the DUT 499, including signals in the analog time domainchannel, the radio frequency domain channel, and/or the digital timedomain (logic) channels. In alternative embodiments, the measurementinstrument may have a time domain channel and a frequency domainchannel, and no logic domain channel, without departing from the scopeof the present teachings.

In FIG. 4 , the oscilloscope 400 includes at least a time domain input410 (e.g., time domain channel, including a receiver), a frequencydomain input 430 (e.g., frequency domain channel, including a receiver),an acquisition system 450, an outer enclosure 401, an integrated LOsignal generator 433, a LO output port 434 (local oscillator outputport), a controller 440, and a display 460. In an embodiment, theoscilloscope 400 may further include a logic domain input 420 (e.g.,logic domain channel, including a receiver). The outer enclosure 401 maybe a housing that houses at least all of the elements of theoscilloscope measurement instrument shown in FIG. 4 .

The time domain input 410 (receiver) receives analog DUT time domainoutput signal 411 from the DUT 499 and may include a time domainreceiver and/or other elements used to process the analog DUT timedomain output signal 411 in the analog time domain channel. The timedomain input 410 provides an analog time domain input signal 412 as anoutput. The time domain input 410 provides the analog time domain inputsignal 412 in a time domain as a first input signal. The logic domaininput 420 (receiver) receives a logic domain signal 421 (logicalsignals) from the DUT 499 and may include a logic domain receiver and/orother elements used to process the logic domain signal 421 (logicalsignals) in the logic domain channel. The logic domain signal 421 haslogic levels determined by the logic domain input 420. The logic domaininput 420 provides a logic level input signal 422 as a second inputsignal.

The frequency domain input 430 (receiver) indirectly receives RF signal431 output from the DUT 499 via the external mixer 462 after theexternal mixer 462 downconverts the RF signal 431 to produce frequencydownconverted IF signal 445. The frequency domain signal may be mmWaveradio frequency signal, for example. The frequency domain input 430receives the frequency downconverted IF signal 445 and provides afrequency domain input signal 432 as an output. The frequency domaininput 430 may include a frequency domain receiver and/or other elementsused to process the frequency downconverted IF signal 445.

The frequency domain input 430 may be controlled by the controller 440to provide the frequency domain input signal 432 as a third input signalthrough the frequency down-conversion. For example, at least oneparameter of the frequency domain input signal 432 (third input signal)may be controlled by control signals (not shown in FIG. 4 ) determinedby the controller 440 in response to the logic levels of the logicdomain signal 421. That is, the controller 440 may control the frequencydomain input 430 based on logic levels provided by the logic domaininput 420 (logical signals) over time. The at least one parameter of thefrequency domain input signal 432 controlled by the controller 440 maybe an acquisition frequency of the frequency domain input signal 432,which is subject to frequency downconversion.

Generally, the controller 440 controls interoperation among the internalLO signal generator 433, the external mixer 462 and each of the timedomain input 410, the logic domain input 420 and the frequency domaininput 430, such that parameters of the internal LO signal generator 433and/or the external mixer 462 may be adjusted in response to data fromany of the time domain input 410, the logic domain input 420 and thefrequency domain input 430, or data from the internal LO signalgenerator 433 and/or the external mixer 462 may be used to controloperations of the time domain input 110, the logic domain input 120 andthe frequency domain input 130.

In addition to controlling interoperation among the time domain input410, the logic domain input 420 and the frequency domain input 430, asdiscussed above with reference to FIG. 1 , the controller 440 is alsoprogrammed to control operations of the integrated LO signal generator433 using control signals 441. The LO signal generator 433 generates anLO signal 435, e.g., using any of various techniques, such as directdigital synthesis (DDS), fractional-N synthesis, or a combinationthereof. The controller 440 may cause the LO signal generator 433 toadjust frequency and/or power of the LO signal 435, for example, inresponse to various data. For example, the controller 440 may determinethe control signals 441 based on the logic levels of the logic domainsignal 421 that it receives from the logic domain input 420. In variousembodiments, the logic domain signal 421 having logic levels over timemay be provided by the DUT 499. The logic levels may represent one ormore parameters of the RF signal 431. For example, the logic levels mayindicate acquisition frequencies set in advance for acquisition of theRF signal 431 by the frequency domain input 430. Also, for example, thelogic domain signal 421 may represent a variable center frequency (e.g.,frequency hopping or sweeping, discussed below) for communications fromthe DUT 499.

The controller 440 may also be programmed to control frequency offsetsof the LO signal 435 for spur dodging based on the logic domain signalsprovided by the DUT 499 when the IF frequency output by the externalmixer 462 is not fixed. Spur dodging avoids certain frequencycombinations of RF and LO inputs to the external mixer 462 that wouldresult in undesired operation. That is, when the IF frequency of the IFsignal 445 has some flexibility, the LO signal 435 may be altered toavoid the spur. The offset in the IF signal 445 may be compensated forin the digital processing subsequent to the FFT, for example. When theLO frequency is moved up by X to avoid a spur, all the downconvertedfrequencies of the IF signal 445 will also be higher by X (assuming useof a superheterodyne receiver), and thus the digital processing willneed to “subtract” X to obtain the correct frequency measure. Thecontroller 440 may use prior knowledge of the external mixer 462 and LOcharacteristics of the LO signal 435 to avoid bad combinations. Forexample, if it is known that the LO signal 435 has a spur and offsetfrequency Y, the controller 440 may control the LO signal generator 433to avoid combinations of RF and LO frequencies where the RF signal mixedwith the spur will fall into the acquisition frequency band.

Alternatively, or in addition, the controller 440 may determine thecontrol signals 441 based on input from another source, such as adatabase, an external processor, or another component, including theexternal mixer 462 itself. For example, the controller 440 may beprogrammed to receive a characteristic of the external mixer 462, suchas desired LO power for a given RF power, conversion gain, knownnon-idealities (e.g., for spur dodging), through an auxiliary controlsignal 463 received from the external mixer 462 as a receivedcharacteristic, and to adjust the integrated LO signal generator 433 toalter the frequency and/or power of the LO signal 435 in response to thereceived characteristic. The controller 440 may receive the auxiliarycontrol signal 463 using a separate electrical connection, such ad asimple serial bus, or the external mixer 462 may have a pre-programmedmemory that communicates with the controller 440 over USB, for example.Of course, the controller 440 may determine the control signals based onother criteria, without departing from the scope of the presentteachings.

With regard to frequency sweeping or hopping of the LO signal 435, thecontroller 440 may be programmed to synchronously adjust parameters ofthe LO signal generator 433 in accordance with parameters of the DUT 499and/or the external mixer 462 to match timing and correspondingfrequencies of the sweeping or hopping. That is, attributes of the LOsignal generator 433, such as the frequency of the LO signal 435, may bemade operative to respond to a specific set of logic levels of the logicdomain signal 421. So, for example, the DUT 499 may be an RF deviceoperating at mmWave frequencies and the carrier frequency of the RFsignal 431 may be hopped across a wide frequency range, e.g., accordingto a predetermined frequency hopping plan implemented by the DUT 499. Tosupport the frequency hopping, the frequency of the LO signal 435 may becorrespondingly hopped under control of the controller 440 insynchronism with the carrier frequency of the RF signal 431 from the DUT499. This results in a baseband signal (the IF signal 445) with a centerfrequency that effectively remains constant, since the LO signal 435 ischanged to maintain the same frequency differential whenever the carrierfrequency of the RF signal 431 changes. That is, the frequency hoppingcomponent is removed, minimizing the bandwidth required to analyze theRF signal 431, and maximizing the achievable signal integrity. Thefrequency control word that hops the carrier frequency of the RF signal431 may be probed by the logic domain signal 421 input to theoscilloscope 400. Coupling the LO attribute (e.g., frequency) to thestate of the logic domain input 420 enables the LO frequency of the LOsignal 435 to hop in response to the frequency control word and achievethe desired results.

The controller 440 may include a memory that stores instructions and aprocessor that executes the instructions. An example of the controller440 is illustrated in and described with respect to FIG. 5 , below. Thecontroller 440 is coupled physically and/or logically (e.g., by a dataconnection) to the logic domain input 420 to determine the logic levelsof the logic domain signal 421 over time. The controller 440 isprogrammed to control operation of the integrated LO signal generator433. In an embodiment, the controller 440 may also be programmed tocontrol operation of the external mixer 462, discussed below. Forexample, when the external mixer 462 is an active mixer, it may haveadjustable gain an amplifier and/or an attenuator stage. In this case,the controller 440 may, after analyzing characteristics of the IF signal445 applied to the frequency domain input 430, alter effective gain ofthe external mixer 462 to best match the amplitude of the RF signal 431and the input characteristics of the frequency domain input 430. Whenthe RF signal 431 is small, gain should be adjusted as early as possibleto optimize noise performance, and when the RF signal 431 is large, itshould be attenuated to prevent distortion.

Although the controller 440 is shown internal to the oscilloscope 400,the controller 440 may be implemented by a processor, host computer orother control device that is outside the oscilloscope 400, such as a PCor computer workstation, for example, without departing from the scopeof the present teachings. That is, the system 40 includes a commoncontrol system, such as the controller 440 or a software programexecuting on a host processor external to the oscilloscope 400, thatcontrols operations of the oscilloscope (e.g., time and/or frequencydomain analysis), as well as the LO generator such that the system 40appears as a unified instrument to the user.

The acquisition system 450 acquires the analog time domain input signal412 output from the time domain input 410, the logic level input signal422 output from the logic domain input 420, and the frequency domaininput signal 432 output from the frequency domain input 430. Theacquisition system 450 produces oscilloscope output(s) 452 based on oneor more of the input signals from the time domain input 410, the logicdomain input 420 and the frequency domain input 430. The oscilloscopeoutput(s) 452 may be provided to a display processor, which formats theoscilloscope output(s) 452 for display on a display device (not shown).For example, each of the analog time domain input signal 412 and thelogic level input signal 422 may be displayed as amplitude (voltage)over time, where the logic level input signal 422 in particular isdisplayed as a stream of high and low voltage values corresponding tothe logic levels of the logic level input signal 422.

The integrated LO signal generator 433 generates the LO signal 435. Theintegrated LO signal generator 433 is embedded internally within theoscilloscope 400. The integrated LO signal generator 433 may generatethe LO signal 435 based on respective states of the logic levels fromthe logic domain input 420. The LO output port 434 is provided in theoscilloscope 400 for outputting the LO signal 435 generated by theintegrated LO signal generator 433 as an output LO signal. The LO signal435 output from the LO output port 434 as the LO signal 435 is outputtedto the external mixer 462.

The external mixer 462 is a frequency mixer that is external to theoscilloscope 400. The external mixer 462 receives the RF signal 431 fromthe DUT 499 at an RF input, and receives the LO signal 435 from the LOoutput port 434 at an LO input. The external mixer 462 frequency mixesthe RF signal 431 and the LO signal 435 to provide the frequencydownconverted IF signal 445 (intermediate frequency signal) at an LOoutput. The frequency downconverted IF signal 445 has a carrier at alower frequency then the RF signal 431. For example, the RF signal 431may have a carrier at a frequency higher than an upper limit of thefrequency domain input 430. In this case, the external mixer 462 may beconfigured to generate the downconverted IF signal 445 to have a carrierat a lower frequency, which is within the limits of the frequency domaininput 430. The external mixer 462 may separately provide acharacteristic of the external mixer 462 to the controller 440 throughthe auxiliary control signal 463, as discussed above, so that thecontroller 440 can use the received characteristic to adjust theintegrated LO signal generator 433 to alter the LO signal 435 inresponse to the received characteristic.

The acquisition system 450 acquires analog time domain input signal 412from the time domain input 410, and frequency domain input signal 432from the frequency domain input 430. The acquisition system 450 may alsoacquire the logic level input signal 422 as a digital time domain inputsignal, from the logic domain input 420. The acquisition system 450produces oscilloscope output(s) 452 based on one or more of the inputsignals acquired by the acquisition system 450 from the time domaininput 410, the frequency domain input 430, and/or the logic domain input420.

The controller 440 may be programed to manage images and non-idealities,resulting from the external mixer 462 mixing the received RF signal 431and the LO signal 435, according to a predetermined frequency plan.Also, the controller 440 may consult a database of non-idealities basedon a model of the external mixer 462 and choose the predeterminedfrequency plan according to the model.

The display 460 is configured to display a variety of featuresrepresentative of functionality of the oscilloscope 400. For example,the display 460 may be configured to display the frequency downconvertedIF signal 445 (frequency domain input signal) as a frequency spectrumwhich corresponds to the RF signal 431. The display 460 is alsoconfigured to display the logic levels from the logic domain input 420as amplitudes versus time, where the amplitudes include high and lowstates. The display 460 may provide a time-aligned display of the logiclevels and frequency domain signals, e.g., the frequency downconvertedIF signal 445 corresponding to the RF signal 431 from the DUT 499.

Generally, enabling the oscilloscope 400 to generate the LO signal 435internally simplifiers the system 40 for the user, since a separatesignal generator is not required. Tight integration is achievableincluding smart power and LO connections, where characteristics of thechosen external mixer 462 may be communicated back to the controller 440and/or the LO signal generator 433 to provide the correct power andfrequency of LO signal 435 through to the external mixer 462 through theLO output port 434. Use of the controller 440, or other common controlsystem as discussed above, enables synchronous adjustment of LOparameters to perform frequency sweeps and spur dodging, for example,discussed above. When the controller 440 software has full control overthe LO signal generator 433 and associated control signals 441, theoscilloscope can also manage the frequency plan, as well as images andnon-idealities associated with mixing by the external mixer 462. Muchtighter time control can be achieved, thereby enabling the oscilloscope400 to perform gated measurements that otherwise would be difficultusing a separate LO signal generator, e.g., connected over a LAN to theoscilloscope 400 and the external mixer 462. Although FIG. 4 shows asingle channel implementation, in which the frequency domain input 430receives the frequency downconverted IF signal 445, various embodimentsinclude a multi-channel implementation, using a common LO signal 35 forphase alignment, as well as separate LO signals for multiple frequencydomain inputs, respectively.

FIG. 5 illustrates a controller in a measurement instrument having time,frequency and logic domain channels, in accordance with a representativeembodiment. The discussion of FIG. 5 references the controller 140,although it is understood that it applies equally to the controller 440,discussed above.

The controller 140 can include a set of instructions that can beexecuted, e.g., by a computer processor, to cause the controller 140 toperform any one or more of the methods or computer-based functionsdisclosed herein. The controller 140 may operate as a standalone deviceor may be connected, for example, using a network, to other computersystems or peripheral devices. Any or all of the elements andcharacteristics of the controller 140 in FIG. 5 may be representative ofelements and characteristics of the controller 140 in FIG. 1 and thecontroller 440 in FIG. 4 , or other similar devices and systems that caninclude a controller and perform the processes described herein.

In a networked deployment, the controller 140 may operate in thecapacity of a client in a server-client user network environment. Thecontroller 140 can also be fully or partially implemented as orincorporated into various devices, such as a central station, an imagingsystem, an imaging probe, a stationary computer, a mobile computer, apersonal computer (PC), or any other machine capable of executing a setof instructions (sequential or otherwise) that specify actions to betaken by that machine. The controller 140 can be incorporated as or in adevice that in turn is in an integrated system that includes additionaldevices. In an embodiment, the controller 140 can be implemented usingelectronic devices that provide video or data communication. Further,while the controller 140 is illustrated, the term “system” shall also betaken to include any collection of systems or sub-systems thatindividually or jointly execute a set, or multiple sets, of instructionsto perform one or more computer functions.

As illustrated in FIG. 5 , the controller 140 includes a processor 142.A processor 142 for a controller 140 is tangible and non-transitory. Asused herein, the term “non-transitory” is to be interpreted not as aneternal characteristic of a state, but as a characteristic of a statethat will last for a period. The term “non-transitory” specificallydisavows fleeting characteristics such as characteristics of a carrierwave or signal or other forms that exist only transitorily in any placeat any time. Any processor described herein is an article of manufactureand/or a machine component. A processor for a controller 140 isconfigured to execute software instructions to perform functions asdescribed in the various embodiments herein. A processor for acontroller 140 may be a general-purpose processor or may be part of anapplication specific integrated circuit (ASIC). A processor for acontroller 140 may also be a microprocessor, a microcomputer, aprocessor chip, a controller, a microcontroller, a digital signalprocessor (DSP), a state machine, or a programmable logic device. Aprocessor for a controller 140 may also be a logical circuit, includinga programmable gate array (PGA) such as a field programmable gate array(FPGA), or another type of circuit that includes discrete gate and/ortransistor logic. A processor for a controller 140 may be a centralprocessing unit (CPU), a graphics processing unit (GPU), or both.Additionally, any processor described herein may include multipleprocessors, parallel processors, or both. Multiple processors may beincluded in, or coupled to, a single device or multiple devices.

Moreover, the controller 140 includes a main memory 144. The main memory144 is representative of any memory included within a controller 140. Inother words, the controller 140 is not limited to only a main memory144, and may include multiple memories and multiple types of memories.Different elements of the controller 140 can communicate with each othervia a bus 145. Memories described herein are tangible storage mediumsthat can store data and executable instructions and are non-transitoryduring the time instructions are stored therein. As used herein, theterm “non-transitory” is to be interpreted not as an eternalcharacteristic of a state, but as a characteristic of a state that willlast for a period. The term “non-transitory” specifically disavowsfleeting characteristics such as characteristics of a carrier wave orsignal or other forms that exist only transitorily in any place at anytime. A memory described herein is an article of manufacture and/ormachine component. Memories described herein are computer-readablemediums from which data and executable instructions can be read by acomputer. Memories as described herein may be random access memory(RAM), read only memory (ROM), flash memory, electrically programmableread only memory (EPROM), electrically erasable programmable read-onlymemory (EEPROM), registers, a hard disk, a removable disk, tape, compactdisk read only memory (CD-ROM), digital versatile disk (DVD), floppydisk, blu-ray disk, or any other form of storage medium known in theart. Memories may be volatile or non-volatile, secure and/or encrypted,unsecure and/or unencrypted.

Although not shown, the controller 140 may further include or beconnected to a video display unit, such as a liquid crystal display(LCD), an organic light emitting diode (OLED), a flat panel display, asolid-state display, or a cathode ray tube (CRT). Additionally, thecontroller 140 includes an input device 143 which receives the logiclevels 123 from the logic domain input 120. The controller 140 alsoincludes a signal generation device 146 which outputs the controlsignals 141 based on the logic levels, in accordance with determinationsby the processor 142.

Instructions stored in the processor 142 and/or the main memory 144 canbe read. The instructions, when executed by the processor 142, can beused to perform one or more of the methods and processes as describedherein. In an embodiment, instructions may reside completely, or atleast partially, within the main memory 144, within another memory,and/or within the processor 142 during execution by the controller 140.

In an alternative embodiment, dedicated hardware implementations, suchas application-specific integrated circuits (ASICs), programmable logicarrays and other hardware components, can be constructed to implementone or more of the methods described herein. One or more embodimentsdescribed herein may implement functions using two or more specificinterconnected hardware modules or devices with related control and datasignals that can be communicated between and through the modules.Accordingly, the present disclosure encompasses software, firmware, andhardware implementations. Nothing in the present application should beinterpreted as being implemented or implementable solely with softwareand not hardware such as a tangible non-transitory processor and/ormemory.

In accordance with various embodiments of the present disclosure, themethods described herein may be implemented using a hardware computersystem that executes software programs. Further, in an exemplary,non-limited embodiment, implementations can include distributedprocessing, component/object distributed processing, and parallelprocessing. Virtual computer system processing can be constructed toimplement one or more of the methods or functionality as describedherein, and a processor described herein may be used to support avirtual processing environment.

FIG. 6 illustrates an operational process for a measurement instrumenthaving time, frequency and logic domain channels, in accordance with arepresentative embodiment.

In FIG. 6 , various subprocesses of the operational process illustratedtherein may be performed fully or partially in parallel, such as fullyor partially simultaneously. However, unless specified, simultaneousprocessing is not particularly required.

In FIG. 6 , the DUT 199 transmits a frequency control word as analogvalues of a logical signal at S601. The analog values of the logicalsignal are captured and quantized by the logic domain input 120 at S602.At S604, digital values of the logical signal are obtained.

At S621, the DUT 199 transmits a time domain signal. The time domaininput 110 obtains the inputs of the time domain signal at S624.

At S641, the DUT 199 transmits a frequency domain signal. The frequencydomain signal is captured at S642 according to a local oscillatorfrequency of the LO signal 135, as varied by a LO signal generator. AtS643, the captured frequency domain signal is downconverted. At S644,inputs of the frequency domain signal are obtained.

At S651, logic levels of the logical signal are displayed, such as onthe display 160. As shown in FIG. 6 , the process at S651 may alsoinclude displaying amplitude versus time, e.g., for the DUT time domainoutput signal 111, and/or amplitude versus time, e.g., for the DUTfrequency domain output signal 131. At S652, the logic levels of thelogical signal are analyzed, such as by the processor 142 of thecontroller 140. At S653, a center frequency of a desired frequencydomain signal is determined, and at S654, the local oscillator iscontrolled in accordance with the center frequency determined at S653.The local oscillator S654 provides the LO signal 135 for use by theinternal mixer 139 in capturing the frequency domain signal according tothe local oscillator frequency indicated by the LO signal 135.

FIG. 7 illustrates another operational process for a measurementinstrument having at least time and frequency domain channels, as wellas an internal (integrated) LO signal generator and an LO output portfor outputting an LO signal generated by the LO signal generator, inaccordance with a representative embodiment. In the depicted process, itis assumed that the measurement instrument also includes a logic domainchannel.

Referring to FIG. 7 , at S710, the oscilloscope 400 generates the LOsignal 435 internally. For example, the oscilloscope 400 may include theintegrated LO signal generator 433 for generating the LO signal 435internally. At S715, the LO signal 435 is output from the oscilloscope400 to the external mixer 462 through LO output port 434. The externalmixer 462 is external to the oscilloscope 400.

At S720, the external mixer 462 downconverts the RF signal 431 receivedfrom the DUT 499, by mixing the LO signal 435 received from theintegrated LO signal generator 433 and the RF signal 431, in order toprovide the frequency downconverted IF signal 445. The LO signalgenerator 433 may be controlled based on logic levels provided via thelogic domain input 420 to manage the downconversion of the frequencydownconverted IF signal 445, e.g., through frequency adjustment of theLO signal 435.

At S725, the frequency downconverted IF signal 445 is received by thefrequency domain input 430 of the oscilloscope 400. The frequencydownconverted IF signal 445 represents the original frequency domainsignal from the DUT 499 (RF signal 431).

At S730, the frequency and/or power of the LO signal 435 may becontrolled to adjust the downconverted IF signal 445 provided by theexternal mixer 462 to the frequency domain input 430. As will beevident, S730 is not necessarily performed after S725 and other steps ofFIG. 7 already described. Rather, S730 may be performed on an ongoingbasis, such as commensurate with S710 in order to control the frequencyand/or power of the LO signal 435 when the LO signal 435 is generatedwithin the oscilloscope 400. For example, as discussed above, whenfrequency hopping is performed by the DUT 499, the LO signal generator433 may be controlled to synchronously hop frequencies of the LO signal435 so that the resulting frequency downconverted IF signal 445 remainssubstantially the same at the different frequencies of the RF signal431. Additionally, the process at S730 is optional in that theadjustment of a downconverted IF signal 445 is not necessary in order toperform other processes shown in FIG. 7 and described herein.

At S735, a frequency spectrum of the frequency downconverted IF signal445 is displayed, such as by the display 460. The frequency spectrum ofthe frequency downconverted IF signal 445 corresponds to the RF signal431 input to the external mixer 462. When frequency hopping is performedby the DUT 499, and managed by synchronously adjusting the frequency ofthe LO signal 435, the frequency hopping is effectively removed in thefrequency downconverted IF signal 445.

At S740, the oscilloscope 400 of FIG. 4 may optionally receive a logiclevel input provided via multiple logic domain input 420 over time invarious embodiments. An example of the logic level input may be a FCW,which represents the center frequency of a hopped signal (e.g., the RFsignal 431) from DUT 499. In other words, the logic level input may besent from the DUT 499 to coordinate acquisitions with the oscilloscope400 in advance, such as by using a predetermined pattern expressed bythe FCW. S740 is not necessarily performed after S735 and other steps ofFIG. 7 already described.

FIG. 8 illustrates another operational process for a measurementinstrument having time and frequency domain channels, as well as aninternal (integrated) LO signal generator and an LO output port foroutputting an LO signal generated by the LO signal generator, inaccordance with a representative embodiment. In the depicted process, itis assumed that the measurement instrument also includes a logic domainchannel.

In FIG. 8 , processes for logic domain input 420, the time domain input410 and the frequency domain input 430 are shown in parallel prior toS851. However, the processes do not have to occur in parallel, and mayinstead be partially commensurate or not commensurate at all.

At S801, the DUT 499 transmits analog logic level signals to theoscilloscope 400. At S802, each bit of the analog logic level signals iscaptured and quantized at the logic domain input 420 to ascertain logiclevels of the analog logic level signals. At S804, digital values of thelogical signal are obtained.

At S821, the DUT 499 transmits a time domain signal to the oscilloscope400. At S824, inputs of the time domain signal are obtained by the timedomain input 410 of the oscilloscope 400.

At S841, the DUT 499 transmits a frequency domain signal, the RF signal431, to the external mixer 462. At S842, the external mixer 462 capturesand downconverts the frequency domain signal from the DUT 499 byfrequency mixing it with the LO signal 435 output by the LO signalgenerator 433, to obtain the frequency downconverted IF signal 445. Asdescribed above, the LO signal 435 itself may be adjusted in response tothe digital values of the logical signal obtained at S804. At S844, thefrequency domain input 430 obtains the inputs of the frequencydownconverted IF signal 445. The inputs of the downconverted IF signal445 are representative of the original frequency domain signal from theDUT 499, e.g., prior to hopping and any frequency upconversion by theDUT 499.

At S851, the controller analyzes logic levels of the logical signalobtained at S804, to obtain respective states of the logic levels. AtS852, the display 460 displays logic levels of the logical signal,and/or a frequency spectrum of the frequency downconverted IF signal445.

At S853, one or more controller operations are performed by thecontroller 440. Examples of controller operations performed by thecontroller include the following. The controller 440 may control atleast one parameter of the frequency domain input signal (e.g., thefrequency downconverted IF signal) in response to respective states ofthe logic levels from the logic domain inputs. The at least oneparameter may be or include, for example, frequency and/or amplitude ofthe frequency domain input signal. The controller 440 may synchronouslyadjust parameters of the integrated LO signal generator 433 to enablefrequency hopping and/or sweeping of the LO signal 435. The controller440 may control frequency offsets of the LO signal 435 for spur dodging.The controller 440 may receive a characteristic of the external mixer462 through an auxiliary control signal 463 received from the externalmixer 462 as a received characteristic, and may adjust the integrated LOsignal generator 433 to alter at least one of frequency and power of theLO signal 435 in response to the received characteristic from theexternal mixer 462. The controller 440 may control the integrated LOsignal generator 433 to generate the LO signal 435 (or multiple suchsignals) having different frequencies at different times according to apredetermined frequency plan. The controller 440 may manage images andnon-idealities resulting from the external mixer 462 mixing the RFsignal 431 and the LO signal 435, according to a predetermined frequencyplan. The controller 440 may, for example, consult a database ofnon-idealities based on a model of the external mixer and choose thepredetermined frequency plan according to the model.

At S854, the integrated LO signal generator 433 generates the LO signal435. As an example, the LO signal 435 may vary according to frequencyhopping as instructed by a FCW provided in the analog logic levelsignals from the DUT 499.

At S855, the LO output port 434 outputs the LO signal 435 to theexternal mixer 462 external to the oscilloscope 400. At S856, the centerfrequency of the desired frequency domain signal input at S842 isdetermined by the controller 440, such as based on the FCW from the DUT499. At S857, the integrated LO signal generator 433 is controlled toemit the LO signal 435 using the center frequency of the desiredfrequency domain signal as determined by the controller 440 at S856.

As described above, a measurement instrument having time, frequency andlogic domain channels enables an oscilloscope 400 to process mmWave RFsignals even when bandwidths much larger than 2 GHz are used by DUT 499.A mixer such as external mixer 462 external to the oscilloscope 400 canbe used for the frequency downconversion. Moreover, analog logic levelsignals input to a logic domain input can be used to enable processingof frequency-hopped spread spectrum signals even when the oscilloscope400 is provided with the time domain input 410 and the frequency domaininput 430.

Although measurement instrument having time, frequency and logic domainchannels has been described with reference to several exemplaryembodiments, it is understood that the words that have been used arewords of description and illustration, rather than words of limitation.Changes may be made within the purview of the appended claims, aspresently stated and as amended, without departing from the scope andspirit of measurement instrument having time, frequency and logic domainchannels in its aspects. Although measurement instrument having time,frequency and logic domain channels has been described with reference toparticular means, materials and embodiments, measurement instrumenthaving time, frequency and logic domain channels is not intended to belimited to the particulars disclosed; rather measurement instrumenthaving time, frequency and logic domain channels extends to allfunctionally equivalent structures, methods, and uses such as are withinthe scope of the appended claims.

The illustrations of the embodiments described herein are intended toprovide a general understanding of the structure of the variousembodiments. The illustrations are not intended to serve as a completedescription of all of the elements and features of the disclosuredescribed herein. Many other embodiments may be apparent to those ofskill in the art upon reviewing the disclosure. Other embodiments may beutilized and derived from the disclosure, such that structural andlogical substitutions and changes may be made without departing from thescope of the disclosure. Additionally, the illustrations are merelyrepresentational and may not be drawn to scale. Certain proportionswithin the illustrations may be exaggerated, while other proportions maybe minimized. Accordingly, the disclosure and the figures are to beregarded as illustrative rather than restrictive.

One or more embodiments of the disclosure may be referred to herein,individually and/or collectively, by the term “invention” merely forconvenience and without intending to voluntarily limit the scope of thisapplication to any particular invention or inventive concept. Moreover,although specific embodiments have been illustrated and describedherein, it should be appreciated that any subsequent arrangementdesigned to achieve the same or similar purpose may be substituted forthe specific embodiments shown. This disclosure is intended to cover anyand all subsequent adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the description.

The Abstract of the Disclosure is provided to comply with 37 C.F.R.§1.72(b) and is submitted with the understanding that it will not beused to interpret or limit the scope or meaning of the claims. Inaddition, in the foregoing Detailed Description, various features may begrouped together or described in a single embodiment for the purpose ofstreamlining the disclosure. This disclosure is not to be interpreted asreflecting an intention that the claimed embodiments require morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter may be directed toless than all of the features of any of the disclosed embodiments. Thus,the following claims are incorporated into the Detailed Description,with each claim standing on its own as defining separately claimedsubject matter.

The preceding description of the disclosed embodiments is provided toenable any person skilled in the art to practice the concepts describedin the present disclosure. As such, the above disclosed subject matteris to be considered illustrative, and not restrictive, and the appendedclaims are intended to cover all such modifications, enhancements, andother embodiments which fall within the true spirit and scope of thepresent disclosure. Thus, to the maximum extent allowed by law, thescope of the present disclosure is to be determined by the broadestpermissible interpretation of the following claims and theirequivalents, and shall not be restricted or limited by the foregoingdetailed description.

1. A measurement apparatus for measuring signals from a device undertest (DUT), the measurement apparatus comprising: a time domain receiverconfigured to receive from the DUT a time domain signal in a timedomain; a logic domain receiver configured to receive from the DUT alogical signal comprising logic levels over time; a frequency domainreceiver configured to receive from the DUT a frequency domain signal ina frequency domain through frequency downconversion; and a controllercoupled to the logic domain receiver, and configured to determine thelogic levels over time of the logical signal and to control at least oneparameter of the frequency domain signal in response to the determinedlogic levels.
 2. The measurement apparatus of claim 1, wherein the atleast one parameter controlled by the controller includes an acquisitionfrequency of the frequency domain signal which is subject to frequencydownconversion.
 3. The measurement apparatus of claim 1, wherein the atleast one parameter controlled by the controller includes an amplitudeof the frequency domain signal.
 4. The measurement apparatus of claim 1,wherein the controller includes processor and a memory storinginstructions that, when executed, cause the processor to control, basedon the logic levels of the logical signal over time, the at least oneparameter of the frequency domain signal.
 5. The measurement apparatusof claim 1, wherein the logic domain receiver comprises a one-bitquantizer, wherein the logical signal is determined to be a logic zerowhen the logical signal is below a threshold and a logic one when thelogical signal is above the threshold.
 6. The measurement apparatus ofclaim 1, wherein the frequency domain signal comprises a hoppedfrequency domain signal.
 7. The measurement apparatus of claim 6,wherein the determined logic levels comprise a frequency control word(FCW) representing a center frequency of the hopped frequency domainsignal.
 8. The measurement apparatus of claim 7, further comprising: alocal oscillator (LO) configured to generate a LO signal, and to providethe LO signal to an external mixer, outside the measurement apparatus,for mixing the LO signal and a radio frequency (RF) from the DUT toprovide the downconverted frequency domain signal received by thefrequency domain receiver.
 9. The measurement apparatus of claim 8,wherein the controller is further configured to synchronously adjustparameters of the LO in accordance with parameters of the DUT to matchtiming and corresponding frequencies of the hopped frequency domainsignal.
 10. A method for operating a multi-domain oscilloscope,comprising: receiving at the multi-domain oscilloscope a time domaininput signal from a device under test (DUT) at a time domain channel,the time domain input signal being a time domain; receiving at themulti-domain oscilloscope a logic level input signal at a logic domainchannel from the DUT; receiving at the multi-domain oscilloscope afrequency domain input signal at a frequency domain channel from the DUTthrough frequency down conversion, the frequency domain input signalbeing in a frequency domain; determining logic levels over time of thelogic level input signal; controlling at least one parameter of thefrequency domain input signal in response to the determined logiclevels; and controlling acquisition frequencies at which the frequencydomain input signal is received in accordance with the determined logiclevels.
 11. The method of claim 10, further comprising: displaying atleast one of the determined logic levels of the logic level inputsignal, amplitude versus time of the time domain input signal, oramplitude versus frequency of the frequency domain input signal.
 12. Themethod of claim 11, wherein the frequency domain input signal comprisesa hopped frequency domain signal.
 13. The method of claim 12, whereinthe determined logic levels comprise a frequency control word (FCW)representing a center frequency of the hopped frequency domain signal.14. The method of claim 13, further comprising: determining the centerfrequency of a desired frequency domain signal using the FCW.
 15. Ameasurement apparatus for measuring signals from a device under test(DUT), the measurement apparatus comprising: a logic domain receiverconfigured to receive a logical signal comprising logic levels overtime; a frequency domain receiver configured to receive a frequencydomain signal in a frequency domain through frequency downconversion;and a controller coupled to the logic domain receiver, and configured tocontrol, based on logic levels of the logical signal over time, at leastone parameter of the frequency domain signal, wherein the frequencydomain receiver is further configured to receive the frequency domainsignal at acquisition frequencies controlled by the controller inaccordance with the logic levels of the logical signal.
 16. Themeasurement apparatus of claim 15, wherein the at least one parametercontrolled by the controller includes an acquisition frequency of thefrequency domain signal which is subject to frequency downconversion.17. The measurement apparatus of claim 15, wherein the controllerincludes a memory that stores instructions and a processor that executesthe instructions to control, based on the logic levels of the logicalsignal over time, the at least one parameter of the frequency domainsignal.
 18. The measurement apparatus of claim 15, wherein the logicdomain receiver comprises a one-bit quantizer, wherein the logicalsignal is determined to be a logic zero when the logical signal is belowa threshold and a logic one when the logical signal is above thethreshold.
 19. The measurement apparatus of claim 15, wherein thefrequency domain signal comprises a hopped frequency domain signal. 20.The measurement apparatus of claim 19, wherein the logic levels comprisea frequency control word (FCW) representing a center frequency of thehopped frequency domain signal.